The invention relates to methods and apparatus for transporting and positioning micro-mechanical parts.
In terms of micro-mechanical parts, preformed parts are to be understood, and therefore not naturally occurring parts. The term "micro-mechanical part" includes both "oblong" as well as "planar" parts. In respect of oblong micro-mechanical parts, such manufactured parts are to be understood which have a cross-sectional dimension in the order of micrometers or millimeters, but the longitudinal dimensions thereof can be desirably longer. Such oblong micro-mechanical parts can, for example, be micro-surgical needles, threads or wires. The cross section of such manufactured parts can be circular, elliptical, oval, rectangular, triangular or polygonal and also have any desired open or hollow geometries. The cross section can also vary as appropriate along the longitudinal length of the part. In respect of planar micro-mechanical parts, such manufactured parts are to be understood which are substantially planar, namely plate- or disc-shaped, for example. Their thickness dimensions are in the order of micrometers or millimeters, while the length and width dimensions can be substantially greater. The planar micro-mechanical parts can have the most varying surface and edge contours. The micro-mechanical parts can be metallic or parts consisting of plastics or of natural materials such as, for example, natural textile fibers.
Up to now, during the individual processing steps within a production and packaging process, micro-mechanical parts are either transported and positioned by means of a mechanical gripper or handled manually, for example, by means of a pincer. In the case of manual handling, the transport or positioning of micro-mechanical parts previously required the use of microscopes and, in the case of machine handling, the use of very complex mechanical and optical systems. The main problem with current handling methods consists in that the micro-mechanical parts are mechanically gripped and can be easily damaged as the thickness of, for example, a micro-surgical needle can be only 70 .mu.m, for example. As the handling forces are often very large, very slight but undesirable plastic deformation of the manufactured part can occur.
Furthermore, positioning of a micro-mechanical part in the micrometer range is particularly difficult, as the moving mechanical gripper means must be precisely positioned with respect to a micro-mechanical part. In previous handling methods, the problem also exists that the adhesion force between the manufactured part and the tool must be overcome. As soon as the micro-mechanical part has made contact with the tool, a relatively large force is necessary in order to displace it on the tool or to remove it from this again.